ANTAROTIO BENTHOS
115
size of the ovaries. Both species occur in both East and West Antarctica
and are probably circumpolar.
The remaining shelf crinoids all belong to the family Antedonidae.
Promachocrinus kerguelensis Carpenter is the most abundant crinoid in
the Antarctic. Ranging from depths from 10 to 1 080 m, it occurs right
around the Continent and through the Scotia Arc. Other relatively
common species which have a circum-Antarctic distribution are :
Florometra mawsoni A. H. Clark (100-917 m), and Anthometra adriani
(Bell) (189-917 m). Isometra vivipara Mortensen although it has been
collected frequently seems to be confined to the Antarctic Peninsula,
the Falkland Islands and southern South America in depths from 79 to
350 m. Isometra graminea John (194-567 m) seems to be the only species
of Isometra with a circumpolar distribution, Isometra hordea John
having been recorded from several stations along the Scotia Arc and 1.
fktvescens John only from Shag Rocks. Most of the other Antarctic
shelf crinoids have a very restricted range. These are listed by Dearborn
and Rommel (1969, p. 35).
6 . Holothuroidea
There has been little recent work on Antarctic holothurians. Pawson
gave a summary of the group for the Antarctic Map Folio Series (1 969)
but the last published work was Ekman’s definitive paper (1926).
Previous work on the group had been contributed by Perrier (1905) and
Vaney (1906a,b,c, 1909, 1914). Pawson did not consider the deep-sea
order Elasipodida. A high percentage of the species of this group are
now recognized as being cosmopolitan, and while 44 species are known
from Antarctic and Subantarctic waters, the systematics are likely to
be modified when revision is possible.
Amongst the 38 species recorded from the coastal waters of Antarctica, the families Sclerodactylidae, Placothuridae, Vaneyellidae,
Rhopalodinidae, Holothuriidae and Stichopidae are not represented.
Representatives of the families Molpadidae and Apodidae, although
well represented in Subantarctic waters have only one representative
each in the Antarctic waters. Only one representative of the family
Phyllophoridae (Huvelockia seczcnda Vaney) is present although there
are eight species of the deep sea family Synallactidae. A majority of the
species (28) belong to the dendrochirotacean families, Psolidae and
Cucumariidae. Pawson (1969a, p. 37) supposes that the fact that
members of these two latter families seem able to acquire the habit of
viviparity or brood-protecting may well account for their relative
success in Antarctica.
Of the 20 genera amongst which these 38 species are distributed,
115
size of the ovaries. Both species occur in both East and West Antarctica
and are probably circumpolar.
The remaining shelf crinoids all belong to the family Antedonidae.
Promachocrinus kerguelensis Carpenter is the most abundant crinoid in
the Antarctic. Ranging from depths from 10 to 1 080 m, it occurs right
around the Continent and through the Scotia Arc. Other relatively
common species which have a circum-Antarctic distribution are :
Florometra mawsoni A. H. Clark (100-917 m), and Anthometra adriani
(Bell) (189-917 m). Isometra vivipara Mortensen although it has been
collected frequently seems to be confined to the Antarctic Peninsula,
the Falkland Islands and southern South America in depths from 79 to
350 m. Isometra graminea John (194-567 m) seems to be the only species
of Isometra with a circumpolar distribution, Isometra hordea John
having been recorded from several stations along the Scotia Arc and 1.
fktvescens John only from Shag Rocks. Most of the other Antarctic
shelf crinoids have a very restricted range. These are listed by Dearborn
and Rommel (1969, p. 35).
6 . Holothuroidea
There has been little recent work on Antarctic holothurians. Pawson
gave a summary of the group for the Antarctic Map Folio Series (1 969)
but the last published work was Ekman’s definitive paper (1926).
Previous work on the group had been contributed by Perrier (1905) and
Vaney (1906a,b,c, 1909, 1914). Pawson did not consider the deep-sea
order Elasipodida. A high percentage of the species of this group are
now recognized as being cosmopolitan, and while 44 species are known
from Antarctic and Subantarctic waters, the systematics are likely to
be modified when revision is possible.
Amongst the 38 species recorded from the coastal waters of Antarctica, the families Sclerodactylidae, Placothuridae, Vaneyellidae,
Rhopalodinidae, Holothuriidae and Stichopidae are not represented.
Representatives of the families Molpadidae and Apodidae, although
well represented in Subantarctic waters have only one representative
each in the Antarctic waters. Only one representative of the family
Phyllophoridae (Huvelockia seczcnda Vaney) is present although there
are eight species of the deep sea family Synallactidae. A majority of the
species (28) belong to the dendrochirotacean families, Psolidae and
Cucumariidae. Pawson (1969a, p. 37) supposes that the fact that
members of these two latter families seem able to acquire the habit of
viviparity or brood-protecting may well account for their relative
success in Antarctica.
Of the 20 genera amongst which these 38 species are distributed,